This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A005143 M2869 #12 Oct 26 2023 22:48:52 %S A005143 1,1,3,10,45,274 %N A005143 Number of sub-Eulerian graphs with n nodes. %D A005143 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A005143 Peter Steinbach, <a href="/A000088/a000088_17.pdf">Field Guide to Simple Graphs, Volume 1</a>, Part 17 (For Volumes 1, 2, 3, 4 of this book see A000088, A008406, A000055, A000664, respectively.) %K A005143 nonn,more %O A005143 2,3 %A A005143 _N. J. A. Sloane_